Virginia calculates child support from a statutory guideline in Virginia Code § 20-108.2, which sets a presumed support amount based on the parents' combined monthly gross income and the number of children being supported. The statute states that "there shall be a rebuttable presumption in any judicial or administrative proceeding for child support…that the amount of the award which would result from the application of the guidelines set forth in this section is the correct amount of child support to be awarded." In other words, the guideline figure is the starting point and the presumed answer — a court can depart from it, but it must explain why.
The Commonwealth publishes a free official calculator: the Virginia Department of Social Services child support obligation calculator. The courts also publish the worksheets judges actually use — form DC-637 for sole custody and form DC-640 for shared custody. We link to those rather than reproduce them, because the official versions are authoritative and are updated when the schedule changes.
This page explains what those tools are doing, and — more usefully — why the number they produce is so often not the number a Northern Virginia court finally orders.
The three inputs that drive the number
Almost everything comes down to three things.
1. Combined monthly gross income. Both parents' gross monthly incomes are added together. The guideline schedule then gives a basic child support obligation for that combined figure.
2. The number of children. The schedule runs from one child to six or more.
3. The custody arrangement. Sole custody, shared custody and split custody are calculated differently, under separate subdivisions of § 20-108.2 and on separate court worksheets. This is why two families with identical incomes can end up with very different orders.
The basic obligation is then apportioned between the parents, and the calculation accounts for the cost of health care coverage for the child and work-related child care costs, which appear as their own lines on the court's worksheet.
Gross income is where the real fight happens
In our experience this is the single most contested part of a Northern Virginia child support case, and it is the part no calculator can resolve for you. The formula is arithmetic. Deciding what number to put into it is not.
Recurring problems include:
- Bonuses and commissions that vary substantially year to year — should the court use last year's figure, a multi-year average, or a base figure with a mechanism for sharing variable pay?
- Equity compensation such as restricted stock that vests in tranches, common in Loudoun and Arlington households
- Self-employment and business income, where personal expenses may be run through a company and the tax return understates what is genuinely available
- Overtime and second jobs, and whether they are reliable enough to count
- Voluntary underemployment, where a parent reduces their earnings around the time support is set. A court can impute income based on earning capacity rather than accept a suppressed figure.
- Federal and military pay structures, including allowances, which are common across Northern Virginia and are not always treated the way a parent assumes
Two parents can run the official calculator on the same family and get answers thousands of dollars apart per year, purely because they entered different income figures. That disagreement is a legal argument, not a math problem.
Very high incomes fall off the end of the schedule
The published schedule covers combined monthly gross income up to $42,500. Above that ceiling, the statute provides that the obligation is the amount at $42,500 plus a percentage of the income above it — currently ranging from 2.6% for one child up to 5.0% for six children.
That threshold is reached more often in Northern Virginia than in most of the Commonwealth. Note also that the schedule is subject to periodic legislative review, so the figures above are current as of publication rather than permanent.
When a court departs from the guideline
Because the presumption is rebuttable, a Virginia court can order more or less than the guideline figure — but it has to state its reasons on the record. Arguments for deviation typically involve a child's extraordinary medical or educational needs, significant travel costs to exercise visitation, support obligations for other children, or an income figure that the guideline handles poorly.
Deviation is the exception, not the norm. A parent who simply feels the number is unfair will not get far. A parent with documented, unusual costs may.
Why the calculator number is often not the final number
Clients frequently arrive having already run the official calculator, and are surprised when we do not treat the output as settled. Three reasons why.
First, as above, the inputs are contestable. Second, the custody arrangement is usually still being negotiated, and moving between a sole-custody and a shared-custody worksheet can change the result materially — which means the parenting schedule and the support figure are really one negotiation, not two. Third, add-ons such as health care coverage and childcare have to be evidenced, not asserted.
The practical consequence: run the calculator to get oriented, but do not make decisions — about the house, about a job change, about accepting a schedule — on the strength of its output alone.
Child support questions we are asked most
Is the guideline amount mandatory?
It is presumed correct, not mandatory. Virginia Code § 20-108.2 creates a rebuttable presumption, so a court may deviate if it explains its reasoning.
Does it matter that we share custody equally?
Yes, considerably. Shared custody is calculated on a different worksheet from sole custody. Equal or near-equal time does not automatically eliminate support, particularly where the parents' incomes differ.
Do bonuses and stock count as income?
Generally yes, though how they are counted is frequently disputed. Timing, reliability and whether a grant relates to past or future service all matter.
What if my ex is deliberately earning less?
A court can impute income based on earning capacity where a parent is voluntarily unemployed or underemployed. It requires evidence rather than suspicion.
Can support be changed later?
Yes. Virginia allows modification on a material change in circumstances — a substantial income change, a change in custody, or a change in the child's needs.
Does child support cover college?
Virginia child support generally runs to age 18, with a limited extension for a child still in high school, and further provision where a child is severely and permanently disabled. College expenses are not part of the guideline, though parents can agree to share them in a written agreement — and if they do, that agreement is what governs.
Can we just agree on a figure?
You can agree, but a court reviewing child support still applies the guideline and must be satisfied the agreed figure is appropriate for the child. Support is regarded as the child's right, not purely the parents' to bargain away.
Related reading
For a fuller walk-through of the mechanics see how child support is calculated in Virginia. For the practice area generally, see child support, and for the custody arrangement that drives the worksheet, child custody. Fairfax-specific guidance is on our Fairfax family law attorney page.
Speak with a Virginia child support attorney
Randall J. Borden has handled Northern Virginia support matters for more than thirty years and argues the income question personally. Call 703-385-8722 or contact the office.
This page explains how Virginia's child support guideline operates. It is general information, not legal advice, and no calculator output — including the Commonwealth's own — should be relied on as a prediction of what a court will order in your case.